MEGATRON: Dwarf Galaxy Quenching in the Epoch of Reionization

@misc{attard2026megatron,
  title = {{MEGATRON: Dwarf Galaxy Quenching in the Epoch of Reionization}},
  author = {David Attard and Ilian T. Iliev and Martin P. Rey and Harley Katz and Corentin Cadiou and Nicholas Choustikov},
  howpublished = {arXiv},
  year = {2026},
  month = sep,
  doi = {10.48550/arxiv.2609.37188},
  eprint = {2609.37188},
  archivePrefix = {arXiv},
  url = {https://arxiv.org/abs/2609.37188},
  note = {CC BY 4.0},
}

TY  - UNPB
TI  - MEGATRON: Dwarf Galaxy Quenching in the Epoch of Reionization
AU  - David Attard
AU  - Ilian T. Iliev
AU  - Martin P. Rey
AU  - Harley Katz
AU  - Corentin Cadiou
AU  - Nicholas Choustikov
PY  - 2026
DA  - 2026/09/29
PB  - arXiv
DO  - 10.48550/arxiv.2609.37188
UR  - https://arxiv.org/abs/2609.37188
AB  - Low-mass galaxies during the Epoch of Reionization are expected to form stars in short bursts separated by periods of inactivity, but what regulates this cycle, and how sensitive it is to the modelling of stellar feedback, remains unclear. We use the MEGATRON high-redshift zoom simulation suite, in which four star-formation and stellar-feedback prescriptions are evolved from identical initial conditions, to study the regulation of stellar mass growth in galaxies with M_* ∼ 10^4 − 10^8 M_⊙ at z = 8.5. We classify galaxies as Star-Forming, Mini-Quenched (no significant star formation over the last 10 Myr), or Quenched (no significant star formation over the last 100 Myr). The feedback prescription controls both how often galaxies are quiescent and how this depends on mass. Models with stronger or more clustered feedback yield larger quiescent fractions compared to the fiducial and Varying IMF models. Duty cycles at fixed mass also differ by factors of several between models. The cold gas profiles of Quenched galaxies are consistent with two physically distinct modes of quenching: mechanical gas evacuation, producing compact, cold gas-poor systems, and thermodynamic suppression, retaining a cold but star-formation-inactive reservoir. At these masses, quiescent galaxies fall below un-lensed JWST/NIRCam detection limits, whereas star-forming galaxies of the same mass do not, and consequently flux-limited samples will be biased towards active phases. Measuring the quiescent fraction as a function of stellar mass in lensing fields would provide a direct test of stellar-feedback models at Cosmic Dawn.
ER  -